Translation of parenthesis in Spanish:

The practice in writing and print of using a set of marks to regulate texts and clarify their meanings, principally by separating or linking words, phrases, and clauses, and by indicating parentheses and asides.

Even if the subordinate clauses open up a parenthesis that seems to last for ever, they do close, eventually, in a completed thought.

The parentheses in that sentence are meant to be tongue-in-cheek, and that's really the tone I was aiming for there: a straightforward description with a little bit of irony added.